Sewage treatment system

ABSTRACT

A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet or the like, an incinerator including a housing, means for selectively and periodically delivering the effluent received in the surge tank to the incinerator housing, the incinerator further including a combustion chamber having a stack and means for directing the flames of combustion downwardly against the top surface of the sewage contained within the housing whereby the liquid component of the contained effluent will evaporate and pass through the stack thereby lowering the level of the contained effluent, means for turning off the incinerator when the level of the effluent contained in the incinerator housing is lowered to a predetermined level whereat a layer of effluent having a predetermined thickness will insulate the bottom of the incinerator housing from the flames of combustion.

United States Cornish et al.

[11.] 3,831,534 Aug. 27, 1974 SEWAGE TREATMENT SYSTEM Primary Examiner-Kenneth W. Sprague Inventors: Alan H. C Newington; Attorney, Agent, or Firm-Spencer Smith Ronald E. DeLaney; Robert B. Davis, both of New Britain, all of [57] ABSTRACT (301m A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet [731 Asslgnee: Koehlernaytm" New Bmam or the like, an incinerator including a housing, means Conn for selectively and periodically delivering the effluent [22] Fi d; July 2, 1973 received in the surge tank to the incinerator housing,

the incinerator further including a combustion cham- [21] Appl- 375,840 her having a stack and means for directing the flames of combustion downwardly against the top surface of [52 us. 01. 110/8 (3, 110/9 R the Sewage contained Within the housing whereby the 51 Int. Cl. F23g 5/12 liquid component of the Contained e'ffluerlt will p [58] Field of Search 110/7 R, s R, s c, 9 R, rate and P through the stack thereby lowering the 0 9 E level of the contained effluent, means for turning off the incinerator when the level of the effluent con- 5 References Cited tained in the incinerator housing is lowered to a pre- UNITED STATES PATENTS determined level whereat a layer of effluent having a 3 357 38] 12/1967 St predetermined thickness will insulate the bottom of evens the incinerator h g f the flames f combus 3,622,5ll ll/l97l Plzzo et al.. 110/7 X 3,741,134 6/1973 Roberts 110/8 6 Claims, 1 Drawing Figure 1/ L5 EiE-Eiif-E'E'ZEifi E ow I 0 FLIP FLOP NO on 1 40 k l 101v 36 2:

1 SEWAGE TREATMENT SYSTEM The present invention relates to sewage treatment systems, and more particularly to sewage treatment sys terns which include an incinerator for reducing the sewage to ash.

In conventional systems, sewage is periodically discharged into an incinerator housing and the incinerator is then activated. Flames of combustion are selectively directed downwardly against the top surface of the sewage to effect the evaporation of the liquid component of the sewage and the reduction of the solid waste component to ash. Thermocouples are secured to the bottom wall of the incinerator housing. A rapid rise in the temperature of the bottom wall of the incinerator housing after the sewage has been completely reduced to ash is sensed by the thermocouples and a signal is generated to de-activate the incinerator. Since serious problems would arise if cold sewage was discharged into the incinerator housing to make contact with the bottom wall thereof at this time, the housing is allowed to cool until the bottom wall temperature is reduced to an acceptable level.

It is, accordingly, an object of the present invention to define an insulation layer having a predetermined.

thickness intermediate the flames of combustion and the incinerator bottom wall which is proximate the flames and to maintain this insulation layer throughout the operation of the incinerator.

Among the advantages of the present invention is the provision of an incinerator wherein sewage or the like having a relatively cold temperature can be discharged into the incinerator housing at any time without deleteriously affecting the incinerator housing whereby the capacity of the incinerator will be substantially increased thereby permitting a reduction in size of the incinerator.

Other objects and advantages of the present invention will become apparent from the following portion of this specification and from the accompanying drawing which illustrates in accordance with the mandate of the patent statutes a presently preferred embodiment incorporating the principles of the invention.

Referring to the drawing:

The sole drawing is a diagrammatic illustration of the sewage treatment system made in accordance with the teachings of the present invention.

The sewage treatment system includes at least one recirculating toilet in which effluent flushed from a toilet fixture is collected in a receiving chamber and a portion of the liquid component of the effluent is filtered and periodically recirculated to the toilet fixture as the flushing medium. After the liquid portion of the effluent becomes spent, the entire contents of the receiving chamber is discharged into a surge tank or the like 12. The contents of the surge tank is periodically pumped by a sewage pump 14 into the housing 16 of an incinerator and the incinerator controls 18 are selectively actuated to cause combustion to take place within the incinerator combustion chamber 20 with flames being discharged through a plurality of flame cones 22 to impact against the sewage to evaporate the liquid components of the sewage which are discharged as a gas through the exhaust stack 24 and to convert the solid components of the sewage to ash.

Initially, no sewage is contained within the incinerator housing 16. When the fluid level of the sewage within the surge tank is increased above the minimum level L such as would occur when the recirculating toilet receiving chamber is discharged, a suitable fluid level sensor or switch 24 is closed whereby an ON signal will be conjointly directed to first and second AND gates. Since there is no sewage in the incinerator housing 16, a first housing level sensor or switch 34 which is closed until the sewage level is increased to a first level L sends an ON signal to the first AND gate. The first AND gate is accordingly on and sends a signal to a bistable flip-flop whereby the flip-flop will be set at a first state. When the flip-flop is set in this first state, a second ON" signal will be directed to the second AND gate thereby energizing the sewage pump 14 whereupon sewage will be transferred from the surge tank 12 to the incinerator housing 16.

When the sewage level within the incinerator housing passes a second level L the incinerator controls 18 are energized by means of the closing of a suitable level sensor or switch 36 and gas is discharged under pressure from a fuel nozzle 30 and is ignited by suitable electrodes 32.

The sewage from the surge tank will be transferred into the incinerator housing until the fluid level increases to a predetermined third level L whereat a suitable sensor or switch 38 is closed sending an OFF signal to the flip-flop whereupon the flip-flop will be set at a second state. When the flip-flop is set at the second state, no ONsignal is directed to the second AND gate, and accordingly, the sewage pump is deenergized. No further sewage will be introduced into the incinerator housing until the level of the sewage is reduced to the first level L by means of evaporation of a portion of the liquid component of the sewage whereupon an ON signal will again be directed to the first AND gate to reset the flip-flop to its first state. The sewage pump will accordingly be activated to increase the sewage level to the third level L So long as the liquid level within the surge tank exceeds the minimum surge tank sewage level L the sewage level within the incinerator housing 16 will reciprocate between the first L, and third L sewage levels. Once the level of the sewage within the surge tank decreases to the minimum sewage level L an ON signal will be removed from the second AND gate and the sewage pump will, accordingly, be deenergized. No additional sewage will be introduced into the incinerator chamber 16 until the receiving chamber of the recirculating tank is again discharged into the surge tank thereby again increasing the fluid level to beyond the minimum level L,. The incinerator will continue to burn until sufficient liquid has evaporated from the sewage to reduce the level of the sewage to the minimum level L whereupon the minimum level sensor 36 deenergizes the incinerator thereby tenninating combustion.

A layer of sewage will accordingly be maintained above the bottom plate 40 of the incinerator housing throughout the operation of the incinerator. Since the temperature of this layer will never exceed the boiling point of the fluid, the bottom plate of the incinerator housing will not be subjected to the extremely high combustion temperatures with the temperature of the bottom plate being maintained substantially equal to the boiling temperature of the sewage. The thickness T of the minimum eflluent layer, and hence, the volume of the effluent having the first fluid level L is selected so that the relatively cold effluent being pumped into the incinerator housing at a predetermined rate by the sewage pump will never decrease the temperature of the effluent contained within the housing at a rate substantially in excess of the rate at which the bottom wall of the incinerator housing would cool down which 5 would subject the metallic housing to severe stresses due to temperature differentials.

Whenever the incinerator housing 16 is to be completely cleaned, the sewage pump may be manually energized by a pushbutton switch 42 to completely drain the surge tank and the incinerator controls 18 can be manually energized by a push-button switch 40 whereupon the remaining sewage can be completely reduced to ash with all liquid contained in the sewage being evaporated and exhausted through the stack 24. If desired, temperature sensitive thermocouples can be located on the bottom plate so that automatic shut-off of the manually energized incinerator will take place when the temperature of the bottom plate of the incinerator housing increases a predetermined amount above the boiling temperature of the sewage.

Having thus described our invention, what we claim 1. A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet or the like,

an incinerator including a housing means for selectively and periodically delivering the effluent received in said surge tank to said incinerator housing,

said incinerator further including means for directing flames of combustion downwardly against the top surface of the effluent contained within said housing whereby the liquid component of the contained effluent will evaporate thereby lowering the level of the contained effluent,

means for turning off said incinerator when the level of the effluent contained in said incinerator housing is lowered to a first predetermined level whereat a layer of effluent having a predetermined thickness will insulate the bottom of said incinerator housing from the flames of combustion, and

means for activating said delivering means when the effluent level in said incinerator housing is lower than a predetermined maximum level and when the effluent level in said surge tank exceeds a predetermined minimum level.

2. A sewage treatment system according to claim 1, further comprising means for selectively turning said incinerator on when said effluent level within said incinerator housing is less than said predetermined level whereby the contained effluent can be reduced to ash prior to a cleaning operation.

3. A sewage treatment system according to claim 1, wherein said delivering means includes a sewage pump.

4. A sewage treatment system according to claim 1, wherein said incinerator further includes a combustion chamber having a stack and said combustion chamber includes said directing means.

5. A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet or the like,

an incinerator including a housing adapted to receive effluent from said surge tank, and

means for directing flames of combustion downwardly against the top surface of the effluent contained within said housing whereby the liquid component of the contained effluent will evaporate thereby lowering the level of the contained effluent,

means for energizing said directing means when the level of the contained effluent exceeds a first predetermined level,

means for delivering effluent from said surge tank to said incinerator housing, when the effluent level in said surge tank exceeds a predetermined minimum level, until the effluent level is raised to a predetermined maximum level, and

means for preventing the operation of said delivering means after the level of the contained effluent has been raised to said maximum level until the level thereof has been decreased by evaporative reduction to a fourth level intermediate said first and maximum effluent levels.

6. A sewage treatment system according to claim 5, wherein said incinerator further includes a combustion chamber having a stack and said combustion chamber includes said directing means. 

1. A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet or the like, an incinerator including a housing means for selectively and periodically delivering the effluent received in said surge tank to said incinerator housing, said incinerator further including means for directing flames of combustion downwardly against the top surface of the effluent contained within said housing whereby the liquid component of the contained effluent will evaporate thereby lowering the level of the contained effluent, means for turning off said incinerator when the level of the effluent contained in said incinerator housing is lowered to a first predetermined level whereat a layer of effluent having a predetermined thickness will insulate the bottom of said incinerator housing from the flames of combustion, and means for activating said delivering means when the effluent level in said incinerator housing is lower than a predetermined maximum level and when the effluent level in said surge tank exceeds a predetermined minimum level.
 2. A sewage treatment system according to claim 1, further comprising means for selectively turning said incinerator on when said effluent level within said incinerator housing is less than said predetermined level whereby the contained effluent can be reduced to ash prior to a cleaning operation.
 3. A sewage treatment system according to claim 1, wherein said delivering means includes a sewage pump.
 4. A sewage treatment system according to claim 1, wherein said incinerator further includes a combustion chamber having a stack and said combustion chamber includes said directing means.
 5. A sewage treatment system comprising a surge tank adapted to receive effluent from a recirculating toilet or the like, an incinerator including a housing adapted to receive effluent from said surge tank, and means for directing flames of combustion downwardly against the top surface of the effluent contained within said housing whereby the liquid component of the contained effluent will evaporate thereby lowering the level of the contained effluent, means for energizing said directing means when the level of the contained effluent exceeds a first predetermined level, means for delivering effluent from said surge tank to said incinerator hOusing, when the effluent level in said surge tank exceeds a predetermined minimum level, until the effluent level is raised to a predetermined maximum level, and means for preventing the operation of said delivering means after the level of the contained effluent has been raised to said maximum level until the level thereof has been decreased by evaporative reduction to a fourth level intermediate said first and maximum effluent levels.
 6. A sewage treatment system according to claim 5, wherein said incinerator further includes a combustion chamber having a stack and said combustion chamber includes said directing means. 